1. Field of the Invention
The present invention relates to reading forms, and more particularly to detecting when a form (usually of paper) is newly placed in a reader and stops moving.
2. Background Information
Automatic reading of a form has been a requirement for many industries since automatic form reads have become widespread. These machines might be activated or triggered to read a form in many ways; for example, by the agent pressing a button, by an optical switch that is activated by the form breaking a light beam, by a micro-switch that is physically activated by the form, or by a camera that detects the presence of a form by detecting a light area (the form) within its field of view.
Typically, form reading terminals have a camera with a photo-sensitive surface (arrays of CCDs, photo-diode/transistors, etc.). Optically, the photo-sensitive surface may be positioned a few inches to a foot or more away from a form lying on a platen or a flatbed. The optical focus of the system is on the platen with a depth of focus suitable to accommodate a wide range of types of forms. Herein “camera” is defined broadly as virtually any optical reader.
FIG. 1 represents a known terminal system 2 with a cavity 4 into which a form 6 is fed. Here, the cavity 4 may be largely shielded from external light, and there may be a tractor drive to hold the form 6 flat as it is drawn into the cavity 4. A camera and a light source may be fixed in the cavity 6 and detect the more reflective forms by the additional light reflected to the camera as compared to a blackened platen.
In other systems, the platen or flatbed bearing the form may be relatively open and easily accessible, and thus easy to use. In these systems, ambient light reflects more from the form rather than platen sending more light energy to a camera. The increase in light energy striking the camera from the form's white area is used to detect the presence of a form and the relative constancy of the energy or the white area content is used to determine the presence and stillness, respectively, of the form. In this and similar applications, however, limitations are present. For example, the user's proximity to the terminal may cast a shadow, the user's hand may enter the camera's field of view, any ambient lighting may change as lights are turned on or off and the time of day changes, and the user's clothing or jewelry may add reflected light.
Beyond external and ambient problems, still other problems may occur as a result of the operation of the system or the camera. For example, the machine may have difficulty determining when the form is still. Repetitive pictures from the camera may continuously show changes in the white content that might be the form moving or the ambient light changing or a shadow being removed, etc. It may be difficult to determine the presence and stillness of a form in these known systems. Since the scene is measured by a camera with camera electronics outputting a video stream, for example, electronics must process the video stream. The scene is analyzed and thresholds set to indicate the new presence of a motionless form. However, to determine the presence and stillness of a form requires time and processing power, and repeating the effort is inefficient and possibly erroneous if the yes/no thresholds are lowered or raised to quicken the process.
If the white content thresholds are reduced, to indicate that a form was inserted and still, it may result in moving tickets being measured and light changes being recognized as newly inserted forms. Either case may result in errors. Raising the threshold may result in forms not being recognized. Both of these cases will likely result in ticket agent and user frustration. Hereinafter, the term “form” refers to any paper product that may be machine read, such as tickets or printed slips. In some applications, the forms may include gaming tickets and play slips.
It would be advantageous to have an easy to use terminal with a platen relatively open to the local environment. But the above listed limitation must be overcome.